Many types of fixed bed catalyst support and retention devices have been used over the decades of chemical plant experience. Many of these devices were small and resulted in a high pressure drop of the reactors in operation. Many of the larger devices were required to be installed in the reactor pressure vessel at fabrication before closure heads were welded into place. Many of the earlier devices were also shaped as straight beams that crossed the lower tangent line of the reactor vessel in a horizontal axis to form a circular disc.
There is a need for an improved catalytic reactor with a support having a design that allows supporting of fixed pellet-type catalyst beds within the reactor pressure vessel, to prevent catalyst migration downstream while imposing the minimum possible pressure drop of the reacting fluid passing through the reactor vessel. Also needed is a support grid for a catalytic reactor that may be easily installed through a limited diameter opening in the reactor vessel. Lower catalyst bed support systems that reduce or eliminate empty or dead spaces at the bottom of conventional reactors, as well as catalyst bed support systems that allow refiners to load increasing amounts of catalyst materials into a reactor without resorting to use of inert catalyst support particle beds, which degrade over time and add significant operating costs to the refinery, are also needed.